Plastic parts that are produced using known injection-molding methods are characterized by high strengths as well as good surface qualities and low production costs. The same applies to components made of cast concrete, gypsum or other hardening materials. However, the production of corresponding casting molds is relatively expensive, since they require a high degree of precision.
Methods for building objects in layers, for example 3D printing methods, such as rapid prototyping, make it possible to produce objects with a good level of precision quickly and cost-effectively. It would therefore be desirable to use methods of this type to produce casting molds for hardening materials. However, the porosity of the casting mold produced using a layering method has a negative effect on the surface quality as well as on the setting and mold filling behavior of hardening materials.
The problem of breaking a casting out of the mold has also not been satisfactorily solved up to now.
DE 691 25 064 T2 describes a method for casting a product in a mold using complex shapes such as undercuts or cavity configurations. In this method, water-soluble casting mold cores made of a particulate material as well as a water-soluble carbohydrate, which may be dissolved with water after casting, are produced. However, the castable materials do not penetrate the mold, since the latter is not porous on the boundary surface.
DE 195 25 307 A1 discloses a casting core which is produced from a dry substance which is solidified with the aid of a binder. The casting core is dissolved and washed out with the aid of water after a casting is produced. The casting core is produced from dry sand or perlite as well as from disodium phosphate as the water-soluble binder.
DE 10 2005 019 699 B3 describes a method for producing a three-dimensional object from metal salt particles as a casting mold or casting core. For this purpose, the three-dimensional object is used in a layering method made of particles which comprise monovalent or polyvalent, water-soluble and/or alcohol-soluble metal salts.
None of the cited prior-art documents discloses or suggests the present invention.
A crucial disadvantage in using casting molds produced using a powder bed-based layering method is the porosity thereof, which results from the use of a powder material. This porosity in an obstacle to the production of exact and dimensionally accurate castings from hydraulically setting materials.
Another disadvantage of known methods is the ability [sic; disability] to easily and completely separate the molds needed for the casting process from the molded part to be produced. Moreover, absorbent components according to the prior art are not suitable for processing hydraulically bound casting materials.